Thinking about precision strikes and how they function, trying to come up with the best combat setup for a combat role for just debuffing.

Considering a toss up between:
Blade/Twitchy (in theory could switch to a 3AP blade with -1ap grip, so 2ap, many more attacks per round)
Brawler/Twitchy (use a 2ap or 3ap melee weapon plus the extra 10% bonus perk)
Pistols/Psycho (Main upside is I don't have to close to melee constantly, but if enemy is in cover, I might still have to constantly use ap to move)

Has anyone tried a debuff character and liked it? Or is the meta such that killing > debuffing nine times out of ten?

I've personally always thought Energy Weapons were an excellent choice for debuffing. Some can be fired for 3 AP, while others can be fired at extreme ranges, they can take a lot of accuracy-boosting weapon modifications, and none of them suffer any penalties for short or long range. It doesn't hurt that their ammunition is relatively easy to get, too.

Energy weapons can't really dish out pain in the Director's Cut, not even against robots - but they can be pretty useful as dedicated debuffers.

I normally use sniper rifles or assault rifles for debuffing - anything that has high range and accuracy would work really. Playing Supreme Jerk, debuffing is how I survive the toughest encounters, it's an essential part of my tactics.
In the end, you have quite some freedom in creating a debuff built; just make sure that the character can shoot at least twice per turn. This requires action points, the right perks, and a high initiative would be useful too. Even with an assault rifle you may end up shooting 3 times per turn.

On paper, the Heavy Weapons specialist has the most debuffing perks; it's a kind of a fixer upper though, and can't place aimed shots. A pistol specialist can shoot frequently, but the range is kind of limited. I would personally stick to Assault Rifles or Sniper Rifles.